Creating .gpx Trail Files from GeoPDF Maps

[Talon]

Being a new member, I first want to say hello and thanks for all the great information posted in this forum.  Wow!  I have worked with GPS units (many brands) for several years now, mostly gathering, editing and converting data (wpts, routes, trails). In the last couple of years I began working with custom mapping and I have a lot to learn.  I spend a lot of time on the water and in the woods hunting, fishing, camping and horseback riding.

My question relates to data extraction from GeoPDF files.  I have downloaded some vintage topo maps from the USGS for some areas that are now covered by lakes.  I would like to create a trail along the river and creek channels of the GeoPDF topo map then export it as a.gpx file for use on my Lowrance locators.  Ultimately, I would like to be able to view the entire contour map while on the lake.

I typically use ExpertGPS or OziExplorer to create trails, but I am not sure how to convert the GeoPDF file for use in these programs.  I also use Mapsource and Fugawi.  If it would be beneficial, I could purchase Global Mapper.

Any thoughts on how to create trails from the GeoPDF's would be greatly appreciated.  I also have a Panasonic Toughbook that I am setting up with GPS capability to use on the water.  This should be a better option than the Lowrance locator for viewing the entire topo map.

[Boyd]

I don't know of any way to extract objects from those GeoPDF files, we discussed this before. GlobalMapper will open a GeoPDF and allow you to export as a GeoTIFF I believe. But this is a raster image (picture) and you would have to trace over the roads you want. I am a version or two behind with Globalmapper though, so maybe the current version lets you do this? Regardless, it's a rather expensive piece of software (but well worth it if you make your own maps).

[edit]Just realized you are talking about scans of historical topo maps and not the new USGS 'US Topo' project. In that case, you would definitely need to manually trace over any trails you want and Globalmapper would be a good program for that. You can download the free trial here although it will not export anything. http://www.bluemarblegeo.com/global-mapper/

[Talon]

Thanks for the help and quick reply.  I downloaded a 1949 topo map from USGS's National Map Viewer and it was delivered in the GeoPDF format.  This is the first time I have worked with GeoPDF's.  Nothing I have will import them, including Fugawi.

I have manually created several trails in ExpertGPS and OziExplorer by tracing river channels on the topo map downloads built into those programs.  It takes a little time but works fine as long as the trail file can be exported as a .gpx.  Most marine locators will read this format.

If Global Mapper will open a GeoPDF, maintain the georeferencing, and allow the creation of a manual trail for .gpx export that would be perfect.

[Boyd]

Yes it will. But I had forgotten about this, which would be a cheaper option. You could convert the geoPDF to a "custom map" (.kmz file) that Basecamp will load. You could then use Basecamp to draw the track: http://forums.gpsfiledepot.com/index.php/topic,3010.0.html

The demo version of G-Raster will convert a small section of the GeoPDF to GeoTiff format, which can then be imported directly into G-Raster's Custom Map section; registered version ($5) is currently required for full conversion. This limitation will be removed in the next release, as the GeoPDF converter has problems with some GeoPDF files (non-standard headers), and I don't want people paying for a program that doesn't always work for every GeoPDF file.

Download g-raster here: http://moagu.com/?page_id=155 (leszekp is the author). Of course, GlobalMapper is still a great program that many of us on this site use regularly. Also, from another recent thread...

For paid Windows OS GIS software licensing:
Global Mapper licenses can be had for $339.15 through the Global Mapper forum here, with updates being $139.00.
ESRI ArcGIS for Home (noncommercial personal use only) is only $100.00/yr direct.

[Talon]

I downloaded and registered G-Raster, then converted the entire GeoPDF file into GeoTIFF, then .kmz.  Checked the accuracy of the .kmz with Google Earth and it was excellent.

Basemap loaded the .kmz and I created the river, creek, and roadbed trails easily; then exported them in the desired .gpx format.  Worked perfect on the Lowrance HDS and the trails aligned very well with previous know waypoints.  Mission accomplished.

Thanks for the help and the cost saving leads on Global Mapper.  Sounds like my next investment.  I really like G-Raster.  What a great program.

[popej]

You can convert Geospatial PDF to many other formats with free tool gdal_translate, which is a part of gdal:
http://www.gdal.org/

This release for Windows supports GeoPDF:
http://www.gisinternals.com/sdk/

Gdal utilities are command line programs. Converting GeoPDF to GeoTiff could be as easy as running single command:
>gdal_translate file.pdf file.tiff

[Talon]

Good stuff.  I have downloaded the files and information to begin working with them.